Implantable systems for cardiac rhythm management often employ medical electrical leads, which extend into the venous blood stream and couple a therapy delivery generator device to a surface of the heart. Typically, a medical electrical lead includes one or more electrodes for stimulating the heart and for sensing electrical activity of the heart.
In addition to, or in lieu of electrodes, a medical electrical lead may include one more other types of sensors, for example, a pressure sensor. An exemplary pressure sensor is a microelectromechanical systems (MEMS) capacitive pressure transducer. This type of pressure sensor typically includes a hermetically sealed capsule that contains a gap capacitor and an integrated circuit (IC) chip coupled thereto. Feedthroughs extend through a sidewall of the capsule to couple the IC chip to external contacts, source and ground, and the contacts are coupled to conductors extending within the lead body. Examples of this type of sensor are described United States pre-grant patent publications 2007/0107524 and 2007/0199385, which are hereby incorporated by reference in their entirety.